1. Field of the Invention
The present invention relates generally to a water cutoff junction member for concrete products to be joined together, and more particularly to a junction member capable of simply and securely joining concrete products including for example construction materials for underground structures such as concrete box culverts, side channels, U-shaped channels, sewage pipes and common channels, construction materials for ground structures such as tunnels and retaining walls, and building materials such as outside wall panels, inside wall panels and slabs, thereby contributing to improved earthquake-resistant and water cutoff properties.
2. Description of the Related Art
A joining method of joining together concrete products including construction materials such as box culverts, side channels and U-shaped channels must conventionally meet the requirements (a) having a rigid connectivity ensuring a structural integration of the concrete products to be joined together; (b) having a flexibility at the joining points of the concrete products to be joined together in order to ensure earthquake resistant properties; and (c) having water cutoff properties for preventing any leakage of liquid.
In order to ensure the earthquake resistant properties of the underground structures such as the box culverts and the side channels in response to a distortion in the ground caused by a ground displacement like a lateral flow which may occur upon the great earthquake, a method has been recently turned out to be advantageous in which the rigidity of the underground structures is lowered to absorb the deformation of the ground in the form of as flexible structures as possible. In this case, satisfactory water cutoff properties must be secured even though the joining sections of the underground structures have been subjected to a large displacement.
However, there have hitherto existed no joining methods satisfying all the requirements (a) to (c) described above.
Up until now, the underground structures have been joined together by way of example using a joining method as illustrated in FIG. 8.
This method employs a packing 51 or an O-ring made of rubber or synthetic resin and disposed within a receiving port 50a at the front end of a receiving pipe 50 which is a concrete product A to be joined on one hand, into which receiving port 50a there is inserted an insertion pipe 52 which is a concrete product B to be joined on the other hand.
Another method is illustrated in FIG. 9, in which concrete products A and B have on their outer sides attachment parts 53 which are fastened together by means of bolts 54 and nuts 55, with a packing 56 made of rubber or the like intervening by contact bonding between the joining faces 2 of the concrete products A and B to be joined together to thereby achieve a water cutoff function.
In the case of the conventional method of joining the underground structures in the form of the concrete products A and B to be joined together by inserting the insertion pipe 52 via the packing 51 made of rubber or the like into the receiving port 50a of the receiving pipe 50 as shown in FIG. 8, design requirements must be satisfied which includes securing a clearance in the receiving port 50a of the receiving pipe 50, having a friction resistance enough to prevent the packing 51 from being disengaged from the receiving port 50a in its natural connecting state, as well as having to set the press-in limit pressure of the insertion pipe 52 to the maximum. Also, in this joining method, the joining section between the receiving pipe 50 and the insertion pipe 52 is poor in follow-up properties in response to an external force such as tensile force or compressive force which may be caused by a displacement and distortion of the ground and vibrations upon an earthquake, resulting in a water leak through a gap between the packing 51 and the receiving pipe 50 and the insertion pipe 52, thus making it impossible to obtain satisfactory water cutoff properties.
In the case of another joining method as shown in FIG. 9 in which by fastening the bolts 54 and the nuts 55 together the packing 56 made of rubber or the like is contact bonded 6 to the joining faces 2 of the concrete products A and B to be joined, the flexibility between the joined concrete products A and B are remarkably impaired, resulting in poor earthquake resistant properties. Also, the water cutoff function is merely effected by a contact bonding force of such a level as to impart an elastic deformation to the packing 56, resulting in insufficient water cutoff properties.
In addition, the joining method illustrated in FIG. 9 entailed deficiencies that it requires a large number of components, a skilled technique for joining the concrete products A and B to be joined together, and a lot of time and labor for the joining work, leading to poor workability and inefficiency as well as a raise in construction costs, material costs and production costs.